AI-Associated Joint Pain Curtailed by Exercise Program

Photo Courtesy © SABCS/Todd Buchanan 2013

Melinda L. Irwin, PhD, MPH

A new study reported at the 2013 San Antonio Breast Cancer Symposium shows that a prescribed exercise program reduces joint pain in breast cancer survivors taking aromatase inhibitors (AIs), with pain reductions observed at all levels of exercise. About 20%-30% of patients with hormone receptor (HR)-positive breast cancer who are prescribed AIs are noncompliant. Patients cite arthralgias (joint pain) as the most common reason for discontinuation of AIs. These findings have the potential to improve adherence to AIs, which would in turn reduce the number of breast cancer recurrences.

“AIs play an important role in the effective treatment of HR+ breast cancer. Unfortunately, many women discontinue the drug because of unpleasant side effects. In this study, we discover that exercise improves joint pain, the most common side effect of AI use. These results are a promising first step in developing clinical interventions that can improve AI-associated joint pain, and in turn, AI adherence, breast cancer survival, and quality of life,” stated lead author Melinda L. Irwin, PhD, MPH, associate professor of chronic disease epidemiology at the Yale School of Public Health and co-leader of the Cancer Prevention and Control Research Program at the Yale Cancer Center in New Haven, Connecticut.

Current NCCN recommendations call for 5 years of treatment with an AI after surgery or other primary treatment for postmenopausal women with stage I—III HR+ breast cancer, accounting for nearly 70% of all newly diagnosed cases of breast cancer. However, up to 50% of patients who take AIs report arthralgias or joint pain and stiffness.

Irwin and colleagues mounted a 12-month hormones and physical exercise (HOPE) study to compare the impact of an exercise program versus usual care on 121 breast cancer survivors who were taking AIs for at least 1.5 years and reported at least moderate joint pain. The women had stage I and II breast cancer and were sedentary but able to exercise, she said.

Study participants were randomized in a 1:1 ratio to a year-long exercise program (twice-weekly supervised resistance and strength training sessions plus 150 minutes per week of at least moderate-intensity aerobic exercise such as brisk walking) or usual care (including education about the benefits of exercise). This exercise program is recommended for healthy adults as well as cancer survivors by the American Cancer Society and other organizations. Participants in the experimental arm were provided free gym memberships.

At the end of one year, arthralgias (worst pain, pain severity, and pain interference) were reduced down to mild pain levels by 30% as a result of participation in the year-long exercise program, compared with modest increases or no change in joint pain among participants assigned to usual care.

Improvements with exercise were seen across the board regardless of age, disease stage, cancer treatment (chemotherapy, radiation, or both), and duration of AI treatment. A dose-response was also seen, with participants who attended at least 80% of the supervised exercise sessions having a 25% decrease in worst pain scores, whereas women who attended fewer than 80% of the supervised sessions having a 14% decrease.

Cardiorespiratory fitness also correlated with pain reduction, Irwin noted. Women who experienced a 5% increase in cardiorespiratory fitness had a 29% decrease in worst pain scores compared with a 7% decrease in worst pain scores among women who did not reach that benchmark.

The next group of studies will assess mechanisms that may be influencing the effect of exercise on AI-associated joint pain, such as body weight, inflammation, and muscular strength, as well as the time of onset of pain improvement with exercise.

Irwin MI, Cartmel B, Gross C, et al. Randomized trial of exercise vs. usual care on aromatase inhibitor-associated arthralgias in women with breast cancer. The hormones and physical exercise (HOPE) study. Presented at: the 36th Annual San Antonio Breast Cancer Symposium held December 10-14, 2013, San Antonio, TX. Abstract S3-03.

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